Guess and check, test, trial and error, completion.
<span>(0.1875 moles)(98.004 g/mole) = 18.37575 g </span>
<span>In correct number of significant figures: 18.4 </span>
<span>The half-life of Carbon 14 and radionuclides are used to estimate the absolute (versus relative) age of pre-history items </span>
